It seems that there may be a cross-resistance between pytrethroids and
amitraz in varroa mites in the USA. Yes, of course Miticure strips WERE
effective [several years ago] but that was before the advent of pyrethroid
resistance there. The situation could be different in Europe as the mite
populations, even the species are probably different from those in the USA.

However, there are many cases of apparent amitraz resistance showing up all
over Europe. This is not new - there has been amitraz resistance in varroa
in Eastern Europe for many years, due to illegal and improper use of the
substance.

Coumaphos resistance is now widespread in Italy also.

If the varroa mite uses similar detoxification mechanisms to get rid of
these different pesticides then cross-resistance is a possibility.

It has yet to be proven. What it does mean is that Integrated Pest
Management for varroa control is even more important now. We need to use a
range of techniques and treatments rather than rely on one magic bullet.


Max

Dr Max Watkins
Vita (Europe) Limited
Brook House, Alencon Link
Basingstoke, Hants RG21 7RD  UK

Tel.   +44 (0) 1256 473177
Fax   +44 (0) 1256 473179


-----Original Message-----
From: Informed Discussion of Beekeeping Issues and Bee Biology
[mailto:[log in to unmask]]On Behalf Of bob harrison
Sent: 25 July 2000 14:25
To: [log in to unmask]
Subject: Re: Apivar


Hugo Thon wrote:
>
> Hugo wrote
>
> Apivar has been distributed in Belgium by official bee organizations
> since
> there are (supposed to be) fluvalinate resistant mites in some parts of
> Europe ,
> i.e in 1998 en 1999.

Hello all,
I would add to your post that in the test results i have seen for some
unknown reason the mites resistant to fluvalinate have been resistant to
amitraz. I find this puzzling as in the U.S. the old "Miticur" (amitraz)
strips were very effective against the varroa mites.
Bob Harrison
Odessa,Missouri